1. Field of the Invention
The invention is directed to a turbine including a thrust balancing piston.
2. Description of the Related Art
A turbine of the type mentioned above is known, for example, from U.S. Pat. No. 3,614,255 A. In this turbine having a high-pressure region and an intermediate-pressure region with opposed flows of operating fluid, axial thrusts generated by the high-pressure region and intermediate-pressure region are balanced during normal operation of the turbine in that the axial thrust of the intermediate-pressure region and a substantially constant axial thrust of an axial thrust balancing piston counteract the axial thrust of the high-pressure region. With the blocking of the operating fluid supply to the intermediate-pressure region that is made possible by a valve during a temporary operation of the turbine, a very small counterpressure is brought about compulsorily in a piston chamber of the axial thrust balancing piston, which piston chamber is associated with the intermediate-pressure region, so that there is an increase in the axial thrust on the rotor which is exerted by the axial thrust balancing piston opposite to the flow direction of the operating fluid through the high-pressure region.
It is an object of the present invention to provide a turbine in which the axial thrust of an axial thrust balancing piston can be varied during normal operation of the turbine.